Help with Weekday() (97)

I run a rpt on Monday or Tuesday morning for the previous week. I want to click a button and enter a date range into my form, then run a qry and create the rpt. The date range on the frm has 2 entries, BeginDate and EndDate. The date range has to be from the previous Monday - Sunday. i.e. 9/17/2001 to 09/23/2001, when I click the button on Monday 09/24 or Tuesday 09/25 or Wed, etc. Currently I'm using DateAdd() to get the 7th day back and the 1st day back, but obviously this only works on Monday. I will need a custom function, but I'm just a novice and would very much appreciate some guidance... Thanks.